CVE-2024-26605

Summary

In the Linux kernel, the following vulnerability has been resolved:

PCI/ASPM: Fix deadlock when enabling ASPM

A last minute revert in 6.7-final introduced a potential deadlock when enabling ASPM during probe of Qualcomm PCIe controllers as reported by lockdep:

============================================ WARNING: possible recursive locking detected 6.7.0 #40 Not tainted

kworker/u16:5/90 is trying to acquire lock: ffffacfa78ced000 (pci_bus_sem){++++}-{3:3}, at: pcie_aspm_pm_state_change+0x58/0xdc

          but task is already holding lock:

ffffacfa78ced000 (pci_bus_sem){++++}-{3:3}, at: pci_walk_bus+0x34/0xbc

          other info that might help us debug this:

Possible unsafe locking scenario:

     CPU0
     ----
lock(pci_bus_sem);
lock(pci_bus_sem);

           *** DEADLOCK ***

Call trace: print_deadlock_bug+0x25c/0x348 __lock_acquire+0x10a4/0x2064 lock_acquire+0x1e8/0x318 down_read+0x60/0x184 pcie_aspm_pm_state_change+0x58/0xdc pci_set_full_power_state+0xa8/0x114 pci_set_power_state+0xc4/0x120 qcom_pcie_enable_aspm+0x1c/0x3c [pcie_qcom] pci_walk_bus+0x64/0xbc qcom_pcie_host_post_init_2_7_0+0x28/0x34 [pcie_qcom]

The deadlock can easily be reproduced on machines like the Lenovo ThinkPad X13s by adding a delay to increase the race window during asynchronous probe where another thread can take a write lock.

Add a new pci_set_power_state_locked() and associated helper functions that can be called with the PCI bus semaphore held to avoid taking the read lock twice.

Affected Software

Weaknesses

ADP Enrichment

CVE Program Container

Additional References

• https://git.kernel.org/stable/c/0f7908a016c092cfdaa16d785fa5099d867bc1a3
• https://git.kernel.org/stable/c/b0f4478838be1f1d330061201898fef65bf8fd7c
• https://git.kernel.org/stable/c/ef90508574d7af48420bdc5f7b9a4f1cdd26bc70
• https://git.kernel.org/stable/c/1e560864159d002b453da42bd2c13a1805515a20

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

References

• https://git.kernel.org/stable/c/0f7908a016c092cfdaa16d785fa5099d867bc1a3
• https://git.kernel.org/stable/c/b0f4478838be1f1d330061201898fef65bf8fd7c
• https://git.kernel.org/stable/c/ef90508574d7af48420bdc5f7b9a4f1cdd26bc70
• https://git.kernel.org/stable/c/1e560864159d002b453da42bd2c13a1805515a20

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